greybus: sdio: convert greybus ocr values to mmc ones

It was missing the translation between the ocr vdd values of greybus to
mmc_core values. This would make the detection of range voltage fail.

mmc: host doesn't support card's voltages

Signed-off-by: Rui Miguel Silva <rui.silva@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>